1. Field of the Invention
The present invention relates to an image processing device, an image processing program and an image processing method for processing time-series images captured by a moving imaging device.
2. Description of the Related Art
In recent years, a medical imaging device for sequentially capturing time-series intraluminal images while moving an in-vivo lumen such as a digestive tract has been developed as represented by a capsule endoscope. The imaging device is swallowed from a mouth of a patient, thereafter moves in lumens by peristaltic action or the like and sequentially captures images to transmit to a receiving device outside the body, and is finally excreted to outside the body.
Conventionally, an image processing device for analyzing a state of an object using time-series images obtained by an imaging device such as a capsule endoscope is known (see U.S. Patent Application Publication No. 2003/0077223). The image processing device compares the time-series images continuously captured by the imaging device, which moves in a gastrointestinal tract, to analyze mobility of the gastrointestinal tract. Specifically, the intra-gastrointestinal tract images are compared, action of the object itself and action of the capsule endoscope are analyzed, and the peristaltic action of the gastrointestinal tract is analyzed.
Images obtained by capturing the inside of in-vivo lumens (intraluminal images) are used not only for checking the mobility of the gastrointestinal tract but also for finding a lesion in the lumen such as the gastrointestinal tract. For example, a doctor observes the time-series intraluminal images, which are received by a receiving device outside the body, using a diagnostic workstation and the like. When a diseased site is found, the doctor performs a medical treatment, such as a tissue collection, arrest of bleeding, or resection of the diseased site, by inserting a medical treatment tool again in the body of the patient, or dissecting the body of the patient as needed. In order to efficiently perform such medical treatment, information that indicates a position of a target diseased site in the lumen is required. When the imaging device captures the diseased site, the position of the imaging device at the time of capturing corresponds to the position of the diseased site or the vicinity thereof. Therefore, when the position of the imaging device at the time of capturing is gasped, the position of the diseased site can be estimated.
As the information regarding the position of the imaging device at the time of capturing, information that shows a position of capturing relative to an entrance or an exit of the lumen or relative to a starting or an ending position of a specific organ along the lumen is more useful than information that shows a spatial coordinate in the body. For example, in a case of an organ that changes its shape in the body, such as a small intestine, even when the position of the imaging device at the time of capturing is grasped by the coordinate, the specified position and an actual position of the diseased site do not conform to each other when the organ has changed its shape. When the position of the imaging device at the time of capturing is grasped by the distance from a base point, such as the entrance of the lumen, the position of the diseased site can be known even when the organ has changed its shape. Also, it is important to know the distance between the lesion and the entrance or the exit of the lumen such as the gastrointestinal tract in order to determine a treatment policy. To calculate the movement amount of the capsule endoscope in the lumen from the predetermined position, detecting a magnetic field generated by a single-core coil, which has generated the magnetic field and is provided in an imaging device, by a plurality of coils arranged outside the body is known (see Japanese Patent Application Laid-open No. 2005-198789).